The frequency interval, or step, between medium frequency broadcasts is 9 kHz in Japan and many other countries. However, it is 10 kHz in some countries such as, for example, the USA (in communities such as Hawaii, Los Angeles, etc.) and its neighboring countries (in communities such as Rio de Janeiro etc. ).
This causes no problem if a receiver uses a variable capacitor for tuning in the broadcast signal, because the receiving frequency can be varied continuously by manual operation. However, in a synthesizer receiver, the interval between receiving frequencies is not continuous and is in fact typically fixed at either 9 kHz or 10 kHz. In other words, the synthesizer receiver is able to tune in frequencies at either 9 kHz intervals or 10 kHz intervals from each other. Therefore, if a person who visits various countries on overseas trips carries a synthesizer receiver, he/she will typically need to switch the interval between receiving frequencies for each area of his visit in order to receive broadcast radio signals in that particular country/region/area.
However, the operation of switching the frequency interval is cumbersome, or difficult, for ordinary users. A user may not even know whether the frequency interval between broadcast waves in an area of concern is 9 kHz or 10 kHz. Often, a switch for the frequency interval selection is located at a position on the receiver, such as inside a battery accommodating portion, which prevents unintentional switching. This makes an operation of switching the frequency interval further cumbersome or difficult.
Further, in shipping synthesizer receivers capable of receiving broadcast signals at more than one frequency interval, a maker typically needs to set the frequency interval at 9 kHz or 10 kHz depending upon their intended destination. This increases the number of assembly steps, and provides room for a mistake in the setting to occur during the assembly process. The present invention is directed to solving the above problems.
In the case of medium frequency broadcasts, such as AM+FM broadcasts the service area of a particular broadcast signal is typically more limited in contrast to short wave broadcasts. A receiver is typically not required, nor designed, to be able to receive a medium frequency broadcast transmitted from a relatively distant place. As a result medium frequency broadcasts from countries/regions/areas outside of the country/region/area in which the the receiver is located are not typically expected to be received by the receiver. Thus there is typically no problem presented if a receiver can not receive a medium frequency broadcast transmitted from another country/region/area. Conversely, there occurs no problem even if in other countries (for example; Japan, France, Germany, England or Italy) a receiver cannot receive a medium frequency broadcast transmitted from the USA or any of its neighboring countries.
As described above, the frequency interval between medium frequency broadcasts in the USA and its neighboring countries is different from that of many other countries. That is, the frequency interval of 10 kHz used in the USA is generally limited to a specific area within North America and South America, while most other areas outside of North and South America utilize a frequency interval between medium frequency broadcast of 9 kHz.
On the other hand, in general, synthesizer receivers carried by persons to overseas locations often not only can receive short wave broadcasts but also short wave broadcast signals. Further, these types of common synthesizer receivers often incorporate a clock circuit so as to be able to display the time of a destination place (local standard time) and the UTC time (coordinated universal time, Greenwich time) or some other predetermined reference time.